Introduction

Network visualizations become dramatically more informative when nodes can display data beyond simple labels. Sonnet provides powerful pie chart and donut (ring) node capabilities that let you encode multiple data dimensions directly into each node.

What Are Pie and Donut Nodes?

Pie Nodes divide a circular node into colored segments, showing proportional data (like category distributions or composition breakdowns).

Donut Nodes are ring-shaped visualizations that can show: - Progress/completion (single value 0-1) - Segmented data (multiple proportions in a ring) - Layered information (outer donut + inner pie)

When to Use Each Type

Use Case Recommended Type
Category composition Pie or Segmented Donut
Progress/completion Simple Donut (fill)
Multiple metrics Double Donut
Comparing ratios Segmented Donut
Three+ data layers Donut + Pie combo

Visual Comparison

# Create a simple 3-node network for comparison
adj <- matrix(c(0, 1, 0,
                1, 0, 1,
                0, 1, 0), nrow = 3, byrow = TRUE)

layout <- matrix(c(-1, 0,
                    0, 0,
                    1, 0), nrow = 3, byrow = TRUE)

par(mfrow = c(1, 3), mar = c(2, 1, 3, 1))

# Pie node
splot(adj, layout = layout,
      pie_values = list(c(0.4, 0.3, 0.3), c(0.5, 0.5), c(0.2, 0.3, 0.5)),
      pie_colors = list(c("#E41A1C", "#377EB8", "#4DAF4A"),
                        c("#984EA3", "#FF7F00"),
                        c("#FFFF33", "#A65628", "#F781BF")),
      node_size = 25,
      title = "Pie Nodes")

# Simple donut
splot(adj, layout = layout,
      donut_fill = c(0.7, 0.5, 0.9),
      donut_color = c("#E41A1C", "#377EB8", "#4DAF4A"),
      node_size = 25,
      title = "Simple Donuts (Progress)")

# Segmented donut
splot(adj, layout = layout,
      pie_values = list(c(0.4, 0.3, 0.3), c(0.5, 0.5), c(0.2, 0.3, 0.5)),
      pie_colors = list(c("#E41A1C", "#377EB8", "#4DAF4A"),
                        c("#984EA3", "#FF7F00"),
                        c("#FFFF33", "#A65628", "#F781BF")),
      donut_fill = c(1, 1, 1),  # Use donut mode
      donut_inner_ratio = 0.5,
      node_size = 25,
      title = "Segmented Donuts")

par(mfrow = c(1, 1))

Pie Chart Nodes

Pie chart nodes divide the node area into colored segments proportional to your data values.

Basic Pie Nodes

Use pie_values to specify the proportions for each node. Values are automatically normalized to sum to 1.

# Simple 4-node network
adj <- matrix(c(0, 1, 1, 0,
                1, 0, 1, 1,
                1, 1, 0, 1,
                0, 1, 1, 0), nrow = 4, byrow = TRUE)

# Each node gets a list of values
splot(adj,
      pie_values = list(
        c(0.6, 0.4),           # Node 1: 2 segments
        c(0.3, 0.3, 0.4),      # Node 2: 3 segments
        c(0.25, 0.25, 0.25, 0.25), # Node 3: 4 segments
        c(0.8, 0.2)            # Node 4: 2 segments
      ),
      node_size = 20,
      title = "Basic Pie Nodes with Different Segment Counts")

Customizing Pie Colors

Use pie_colors to specify custom colors for each segment.

# Professional color palette
colors_2seg <- c("#2E86AB", "#A23B72")
colors_3seg <- c("#F18F01", "#C73E1D", "#3B1F2B")
colors_4seg <- c("#1B998B", "#ED217C", "#2D3047", "#FFFD82")

splot(adj,
      pie_values = list(
        c(0.6, 0.4),
        c(0.3, 0.3, 0.4),
        c(0.25, 0.25, 0.25, 0.25),
        c(0.8, 0.2)
      ),
      pie_colors = list(
        colors_2seg,
        colors_3seg,
        colors_4seg,
        colors_2seg
      ),
      node_size = 20,
      title = "Pie Nodes with Custom Colors")

Styling Pie Borders

Customize the border around pie charts using pie_border_width and node border parameters.

par(mfrow = c(1, 2))

# Standard borders
splot(adj,
      pie_values = list(c(0.6, 0.4), c(0.3, 0.3, 0.4),
                        c(0.25, 0.25, 0.25, 0.25), c(0.8, 0.2)),
      node_border_color = "black",
      pie_border_width = 2,
      node_size = 18,
      title = "Dark Borders")

# Colored borders per node
splot(adj,
      pie_values = list(c(0.6, 0.4), c(0.3, 0.3, 0.4),
                        c(0.25, 0.25, 0.25, 0.25), c(0.8, 0.2)),
      node_border_color = c("#E41A1C", "#377EB8", "#4DAF4A", "#984EA3"),
      node_border_width = 3,
      node_size = 18,
      title = "Per-Node Colored Borders")

par(mfrow = c(1, 1))

Real-World Example: Category Distributions

# Social network with interest categories
adj <- matrix(c(
  0, 1, 1, 0, 1,
  1, 0, 1, 1, 0,
  1, 1, 0, 1, 1,
  0, 1, 1, 0, 1,
  1, 0, 1, 1, 0
), nrow = 5, byrow = TRUE)

# Interest distribution per person (Sports, Music, Tech, Art)
interests <- list(
  c(0.5, 0.2, 0.2, 0.1),  # Person 1: Sports fan
  c(0.1, 0.6, 0.1, 0.2),  # Person 2: Music lover
  c(0.2, 0.1, 0.5, 0.2),  # Person 3: Tech enthusiast
  c(0.1, 0.2, 0.2, 0.5),  # Person 4: Artist
  c(0.3, 0.3, 0.2, 0.2)   # Person 5: Balanced
)

interest_colors <- c("#E74C3C", "#9B59B6", "#3498DB", "#2ECC71")

splot(adj,
      layout = "fr",
      pie_values = interests,
      pie_colors = rep(list(interest_colors), 5),
      node_size = 18,
      labels = c("Alex", "Blake", "Casey", "Drew", "Ellis"),
      label_size = 0.9,
      title = "Social Network: Interest Distributions")

Simple Donut Nodes (Progress Rings)

Simple donuts display a single value (0-1) as a filled ring, perfect for showing progress or completion.

Basic Progress Donuts

Use donut_fill with values between 0 and 1 to show progress.

adj <- matrix(c(0, 1, 1, 1,
                1, 0, 0, 0,
                1, 0, 0, 0,
                1, 0, 0, 0), nrow = 4, byrow = TRUE)

layout <- matrix(c(0, 0,
                   -1, 1,
                   1, 1,
                   0, -1), nrow = 4, byrow = TRUE)

splot(adj, layout = layout,
      donut_fill = c(1.0, 0.75, 0.5, 0.25),
      node_size = 22,
      labels = c("100%", "75%", "50%", "25%"),
      title = "Task Completion Status")

Customizing Donut Colors

# Color by completion level
completion_colors <- c("#27AE60", "#F39C12", "#E74C3C", "#95A5A6")

splot(adj, layout = layout,
      donut_fill = c(1.0, 0.75, 0.5, 0.25),
      donut_color = completion_colors,
      node_size = 22,
      labels = c("Done", "Almost", "Halfway", "Starting"),
      title = "Completion with Status Colors")

Showing Values in Center

Enable donut_show_value = TRUE to display the numeric value inside the donut.

splot(adj, layout = layout,
      donut_fill = c(0.95, 0.73, 0.48, 0.22),
      donut_color = c("#3498DB", "#9B59B6", "#E74C3C", "#1ABC9C"),
      donut_show_value = TRUE,
      node_size = 25,
      title = "Progress Rings with Values")

Formatting Displayed Values

Customize value display with prefix, suffix, and digit precision.

par(mfrow = c(1, 3))

# Percentage format
splot(adj, layout = layout,
      donut_fill = c(0.95, 0.73, 0.48, 0.22),
      donut_show_value = TRUE,
      donut_value_suffix = "%",
      donut_value_digits = 0,
      node_size = 22,
      title = "Percentage")

# Prefix format
splot(adj, layout = layout,
      donut_fill = c(0.95, 0.73, 0.48, 0.22),
      donut_show_value = TRUE,
      donut_value_prefix = "$",
      donut_value_digits = 0,
      node_size = 22,
      title = "With Prefix")

# Decimal precision
splot(adj, layout = layout,
      donut_fill = c(0.95, 0.73, 0.48, 0.22),
      donut_show_value = TRUE,
      donut_value_digits = 2,
      node_size = 22,
      title = "2 Decimal Places")

par(mfrow = c(1, 1))

Donut Customization

Controlling Hole Size with donut_inner_ratio

The donut_inner_ratio parameter controls the size of the inner hole (0 = no hole, 1 = all hole).

par(mfrow = c(1, 4))

for (ratio in c(0.3, 0.5, 0.7, 0.85)) {
  splot(adj, layout = layout,
        donut_fill = c(0.8, 0.6, 0.9, 0.7),
        donut_inner_ratio = ratio,
        node_size = 25,
        title = paste("Inner Ratio:", ratio))
}

par(mfrow = c(1, 1))

Background Color for Unfilled Portions

Use donut_bg_color to change the color of unfilled donut sections.

par(mfrow = c(1, 3))

splot(adj, layout = layout,
      donut_fill = c(0.7, 0.5, 0.8, 0.6),
      donut_bg_color = "#EEEEEE",
      node_size = 25,
      title = "Light Gray Background")

splot(adj, layout = layout,
      donut_fill = c(0.7, 0.5, 0.8, 0.6),
      donut_bg_color = "#2C3E50",
      node_size = 25,
      title = "Dark Background")

splot(adj, layout = layout,
      donut_fill = c(0.7, 0.5, 0.8, 0.6),
      donut_bg_color = "transparent",
      node_size = 25,
      title = "Transparent Background")

par(mfrow = c(1, 1))

Polygon Shapes with donut_shape

Transform donuts into polygons: hexagon, square, diamond, triangle, or pentagon.

shapes <- c("circle", "hexagon", "square", "diamond", "triangle", "pentagon")

par(mfrow = c(2, 3))

for (shape in shapes) {
  splot(adj, layout = layout,
        donut_fill = c(0.7, 0.5, 0.9, 0.6),
        donut_shape = shape,
        donut_color = c("#3498DB", "#E74C3C", "#2ECC71", "#F39C12"),
        node_size = 25,
        title = paste("Shape:", shape))
}

par(mfrow = c(1, 1))

Border Styling (Advanced)

Sonnet provides extensive border customization options for donut nodes, including double borders and line type patterns.

Single Border Customization

Use donut_border_color to set the border color.

par(mfrow = c(1, 3))

splot(adj, layout = layout,
      donut_fill = c(0.7, 0.5, 0.9, 0.6),
      donut_border_color = "black",
      node_size = 25,
      title = "Black Border")

splot(adj, layout = layout,
      donut_fill = c(0.7, 0.5, 0.9, 0.6),
      donut_border_color = "#E74C3C",
      node_size = 25,
      title = "Red Border")

# Per-node border colors
splot(adj, layout = layout,
      donut_fill = c(0.7, 0.5, 0.9, 0.6),
      donut_border_color = c("#E74C3C", "#3498DB", "#2ECC71", "#F39C12"),
      node_size = 25,
      title = "Per-Node Colors")

par(mfrow = c(1, 1))

Double Borders with donut_outer_border_color

Create a double-border effect by specifying both inner and outer border colors.

par(mfrow = c(1, 3))

# Classic double border
splot(adj, layout = layout,
      donut_fill = c(0.7, 0.5, 0.9, 0.6),
      donut_border_color = "white",
      donut_outer_border_color = "black",
      node_size = 28,
      title = "White Inner, Black Outer")

# Colored double border
splot(adj, layout = layout,
      donut_fill = c(0.7, 0.5, 0.9, 0.6),
      donut_border_color = "#3498DB",
      donut_outer_border_color = "#2C3E50",
      node_size = 28,
      title = "Blue Inner, Dark Outer")

# Per-node double borders
splot(adj, layout = layout,
      donut_fill = c(0.7, 0.5, 0.9, 0.6),
      donut_border_color = c("#FFD700", "#C0C0C0", "#CD7F32", "#E5E4E2"),
      donut_outer_border_color = c("#B8860B", "#808080", "#8B4513", "#71706E"),
      node_size = 28,
      title = "Gold, Silver, Bronze, Platinum")

par(mfrow = c(1, 1))

Line Types with donut_border_lty

The donut_border_lty parameter accepts R’s standard line type values:

Value Name Description
0 “blank” No line
1 “solid” Solid line (default)
2 “dashed” Dashed line
3 “dotted” Dotted line
4 “dotdash” Dot-dash pattern
5 “longdash” Long dashes
6 “twodash” Two-dash pattern 
lty_values <- c(1, 2, 3, 4, 5, 6)
lty_names <- c("solid", "dashed", "dotted", "dotdash", "longdash", "twodash")

par(mfrow = c(2, 3))

for (i in seq_along(lty_values)) {
  splot(adj, layout = layout,
        donut_fill = c(0.7, 0.5, 0.9, 0.6),
        donut_border_color = "#2C3E50",
        donut_border_lty = lty_values[i],
        node_size = 28,
        title = paste0("lty = ", lty_values[i], " (", lty_names[i], ")"))
}

par(mfrow = c(1, 1))

Per-Node Line Types

Assign different line types to individual nodes.

# 5-node network
adj5 <- matrix(c(
  0, 1, 1, 0, 0,
  1, 0, 1, 1, 0,
  1, 1, 0, 1, 1,
  0, 1, 1, 0, 1,
  0, 0, 1, 1, 0
), nrow = 5, byrow = TRUE)

# Create circle layout manually
n <- 5
angles <- seq(0, 2 * pi, length.out = n + 1)[1:n]
circle_layout <- cbind(cos(angles), sin(angles))

splot(adj5,
      layout = circle_layout,
      donut_fill = c(0.9, 0.7, 0.5, 0.8, 0.6),
      donut_border_color = "#2C3E50",
      donut_border_lty = c(1, 2, 3, 4, 5),
      node_size = 22,
      labels = c("Solid", "Dashed", "Dotted", "DotDash", "LongDash"),
      label_size = 0.8,
      title = "Per-Node Line Types")

Combining Double Borders with Line Types

par(mfrow = c(1, 2))

# Dashed outer border
splot(adj, layout = layout,
      donut_fill = c(0.7, 0.5, 0.9, 0.6),
      donut_border_color = "white",
      donut_outer_border_color = "#E74C3C",
      donut_border_lty = 2,
      node_size = 30,
      title = "Dashed Double Border")

# Different line types per node
splot(adj, layout = layout,
      donut_fill = c(0.7, 0.5, 0.9, 0.6),
      donut_border_color = "white",
      donut_outer_border_color = c("#E74C3C", "#3498DB", "#2ECC71", "#F39C12"),
      donut_border_lty = c(1, 2, 3, 4),
      node_size = 30,
      title = "Mixed Line Types")

par(mfrow = c(1, 1))

Donut + Pie Combinations

For truly data-rich visualizations, combine donut rings with inner pie charts or use multiple donut layers.

Outer Donut Ring with Inner Pie Chart

Use both donut_fill AND pie_values together.

adj3 <- matrix(c(0, 1, 1,
                 1, 0, 1,
                 1, 1, 0), nrow = 3, byrow = TRUE)

layout3 <- matrix(c(-1, 0, 1, 0, 0, 1), nrow = 3, byrow = TRUE)

splot(adj3, layout = layout3,
      # Outer donut: progress/completion
      donut_fill = c(0.75, 0.5, 0.9),
      donut_color = c("#3498DB", "#E74C3C", "#2ECC71"),
      donut_inner_ratio = 0.65,
      # Inner pie: category breakdown
      pie_values = list(
        c(0.5, 0.3, 0.2),
        c(0.3, 0.4, 0.3),
        c(0.2, 0.2, 0.6)
      ),
      pie_colors = list(
        c("#F39C12", "#8E44AD", "#1ABC9C"),
        c("#F39C12", "#8E44AD", "#1ABC9C"),
        c("#F39C12", "#8E44AD", "#1ABC9C")
      ),
      node_size = 30,
      title = "Donut (Progress) + Pie (Categories)")

Double Donut Configuration

Layer two donut rings by using both segmented donuts and progress donuts creatively.

# Use segmented outer donut with a simple fill creating a visual double effect
splot(adj3, layout = layout3,
      pie_values = list(
        c(0.4, 0.35, 0.25),
        c(0.5, 0.3, 0.2),
        c(0.3, 0.3, 0.4)
      ),
      pie_colors = list(
        c("#E74C3C", "#3498DB", "#2ECC71"),
        c("#E74C3C", "#3498DB", "#2ECC71"),
        c("#E74C3C", "#3498DB", "#2ECC71")
      ),
      donut_fill = c(0.8, 0.6, 0.95),
      donut_inner_ratio = 0.55,
      donut_border_color = "white",
      donut_outer_border_color = "#2C3E50",
      node_size = 32,
      title = "Segmented Donut + Inner Pie")

Real-World Examples

Example 1: Project Completion Dashboard

# Project dependency network
proj_adj <- matrix(c(
  0, 1, 1, 0, 0,
  0, 0, 0, 1, 0,
  0, 0, 0, 1, 1,
  0, 0, 0, 0, 1,
  0, 0, 0, 0, 0
), nrow = 5, byrow = TRUE)

# Layout suggesting flow
proj_layout <- matrix(c(
  -2, 0,    # Start
  -1, 0.5,  # Phase 1
  -1, -0.5, # Phase 2
  0, 0,     # Integration
  1, 0      # Deploy
), nrow = 5, byrow = TRUE)

# Completion percentages
completion <- c(1.0, 0.85, 0.6, 0.3, 0.0)

# Color by status
status_colors <- c("#27AE60", "#2ECC71", "#F39C12", "#E74C3C", "#95A5A6")

splot(proj_adj, layout = proj_layout,
      donut_fill = completion,
      donut_color = status_colors,
      donut_show_value = TRUE,
      donut_value_suffix = "%",
      donut_value_digits = 0,
      donut_border_color = "white",
      donut_outer_border_color = "#2C3E50",
      node_size = 20,
      labels = c("Start", "Phase 1", "Phase 2", "Integrate", "Deploy"),
      label_size = 0.85,
      arrow_size = 0.5,
      title = "Project Completion Dashboard")

Example 2: Team Skills Network

# Team collaboration network
team_adj <- matrix(c(
  0, 1, 1, 1,
  1, 0, 1, 0,
  1, 1, 0, 1,
  1, 0, 1, 0
), nrow = 4, byrow = TRUE)

# Skill breakdown: Frontend, Backend, Data, DevOps
skill_colors <- c("#3498DB", "#E74C3C", "#2ECC71", "#F39C12")

skills <- list(
  c(0.1, 0.4, 0.4, 0.1),  # Alice: Backend + Data
  c(0.5, 0.2, 0.1, 0.2),  # Bob: Frontend
  c(0.2, 0.2, 0.4, 0.2),  # Carol: Data focused
  c(0.1, 0.3, 0.1, 0.5)   # Dan: DevOps
)

splot(team_adj,
      layout = "circle",
      pie_values = skills,
      pie_colors = rep(list(skill_colors), 4),
      donut_fill = c(0.9, 0.7, 0.8, 0.85),
      donut_inner_ratio = 0.5,
      donut_border_color = "white",
      node_size = 25,
      labels = c("Alice", "Bob", "Carol", "Dan"),
      label_size = 1.0,
      title = "Team Skills Distribution")

Example 3: Multi-Metric Node Visualization

# 3-node comparison
comp_adj <- matrix(c(0, 1, 1, 1, 0, 1, 1, 1, 0), nrow = 3, byrow = TRUE)
comp_layout <- matrix(c(-1, 0, 1, 0, 0, 1), nrow = 3, byrow = TRUE)

# Outer donut: Overall score
# Inner pie: Score breakdown (Quality, Speed, Cost)
splot(comp_adj, layout = comp_layout,
      # Outer: Overall performance (0-1)
      donut_fill = c(0.85, 0.65, 0.92),
      donut_color = c("#2980B9", "#C0392B", "#27AE60"),
      donut_inner_ratio = 0.6,
      donut_border_color = "white",
      donut_outer_border_color = "#2C3E50",
      donut_border_lty = c(1, 2, 1),  # Dashed for middle node
      # Inner: Breakdown
      pie_values = list(
        c(0.4, 0.3, 0.3),  # Balanced
        c(0.2, 0.5, 0.3),  # Speed focused
        c(0.5, 0.2, 0.3)   # Quality focused
      ),
      pie_colors = rep(list(c("#F1C40F", "#9B59B6", "#1ABC9C")), 3),
      node_size = 35,
      labels = c("Product A", "Product B", "Product C"),
      label_position = "below",
      title = "Product Comparison: Overall Score + Breakdown")

Parameter Reference

Pie Chart Parameters

Parameter Type Default Description
pie_values list NULL List of numeric vectors with proportions per node
pie_colors list/vector Default palette Colors for pie segments
pie_border_width numeric NULL Border width for pie slice dividers

Donut Parameters

Parameter Type Default Description
donut_fill numeric NULL Single values (0-1) for progress donuts
donut_color vector Default palette Colors for donut segments
donut_inner_ratio numeric 0.5 Size of inner hole (0-1)
donut_bg_color character “#EEEEEE” Background for unfilled portions
donut_shape character “circle” Shape: circle, hexagon, square, diamond, triangle, pentagon
donut_show_value logical FALSE Display value in center
donut_value_prefix character “” Prefix for displayed value
donut_value_suffix character “” Suffix for displayed value
donut_value_digits integer 2 Decimal places for displayed value
donut_empty logical TRUE Render empty rings for NA values

Donut Border Parameters

Parameter Type Default Description
donut_border_color character “black” Inner border color
donut_border_width numeric NULL Border width (uses node_border_width if NULL)
donut_outer_border_color character NULL Outer border color (enables double border)
donut_border_lty numeric/character 1 Line type: 0-6 or “blank”, “solid”, etc.

Double Donut Parameters

Parameter Type Default Description
donut2_values list NULL Values for inner donut ring
donut2_colors list NULL Colors for inner donut ring
donut2_inner_ratio numeric 0.4 Inner radius ratio for inner donut

Conclusion

Sonnet’s pie and donut node features transform simple network diagrams into rich, multi-dimensional visualizations. Whether you need to show completion status, category breakdowns, or multiple metrics per node, these tools provide the flexibility to create exactly the visualization you need.

Key takeaways:

  • Pie charts are ideal for showing composition/category data
  • Simple donuts excel at progress/completion metrics
  • Double borders and line types add visual hierarchy
  • Combinations (donut + pie) enable multi-metric displays
  • Custom shapes (hexagon, square, etc.) provide visual variety

For more examples and advanced usage, see the package documentation with ?splot or visit the Sonnet GitHub repository.

Generated by Sonnet package v1.2.7